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Questions tagged [high-availability]

High availability is an architectural consideration often involving degrees of redundancy to insure availability in case of system or component failure.

High availability is an architectural consideration often involving degrees of redundancy to insure availability in case of system or component failure. Highly available systems are commonly implemented in situations where the risk outweighs the cost.

Best practices such as change control, standardized procedures, and monitoring can also enable high availability.

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Error configuring File Share Witness in a Windows 2012R2 Cluster

I'm learning how to configure a simple W2012R2 Cluster for a AlwaysOn Basic Availability Group. I have this VM scenario: - 1 DC (outside the cluster) - 2 SQL Server Standard 2016 (in a Cluster) I've created a File Share in the DC to set it as File…
Farlop
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How does systemd decide if a service is ok or not

This question is related to: reliable systemd service for autossh I have a service which uses type=simple. Here the systemd docs: Type=simple (default): systemd considers the service to be started up immediately. The process must not fork. Do not…
guettli
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Hyper-v failover or replication in 2 node cluster

I'm trying to setup some form of a failover cluster between 2 hosts. I want to be able to have high availability on 2 of my VMs. It seems that some form of shared storage is required for this to work properly in a windows cluster but the goal at the…
phosplait
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How does High Availability work?

I don't understand how to setup a failover for my quite simple scenario. I am building a service gateway for API. What I want to have is two servers hosted in different datacenters. And I simply want the user to be able to access the service even if…
Wapac
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crm_mon -E does not run the external-agent on Debian Jessie

Setup I'm currently having a working 2-nodes HA cluster using Pacemaker+Corosync. My nodes are running on Debian 8 (Jessie). Now I would be able to get notified when changes occur in the cluster (resources stop/start, promote/demote, move...). Since…
Habovh
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Multi-state MySQL master/slave pacemaker resource fails to launch on cluster nodes

Setup I'm setting up an HA cluster for a web application using two physical servers in a Corosync/Pacemaker managed cluster. After finding out I was heading the wrong way, I decided to use heartbeat's bundled MySQL resource agent to manage my MySQL…
Habovh
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Two-node VMware HA cluster - admission control policy?

I normally setup larger clusters than a 2-node cluster with shared storage, but we have built a cluster specifically for hardware based GPU's for a few VMs and thus new hardware and just a 2-node cluster with backend shared SAN storage. The 2 hosts…
TheCleaner
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High Availability iSCSI Target Options

I have two servers (Intel Xeon) with running ESXi on them. There are about 70 clients in the network (16 thin clients among them). We've got pretty large data storage (it's about 100TB). We're using Exchange 2010 CCR and SQL DB with critical data.…
ToreTrygg
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How to Reduce Failover Interval in HAProxy?

I have setup HAProxy and it is working fine. I observed that when one of the node goes down HAProxy detects that immediately, but switch-over / redirect existing traffic to the rest of working nodes took 15-16 seconds (I checked like 50 times with…
Never Quit
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Dell switches, LAG config, ports stay lit when device powered off

I have two Dell switches configured in a stack (with stacking cables). I have four ports on each unit in the stack configured in two separate LAGs as follows: Unit 1/P1: LAG1 Unit 1/P2: LAG1 Unit 1/P3: LAG2 Unit 1/P4: LAG2 Unit 2/P1: LAG1 Unit…
Alan Murrell
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HAProxy failing at random times (backend has no server available!)

I have a CentOS 7.1 (x64) droplet configured to load balance between 2 apache/php servers. I have it working perfectly, but randomly throughout the day it reports the following: haproxy[12947]: backend app_backend has no server available! HA Proxy…
rosey85uk
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How to configure Failover IPs for High Availability with Hetzner Online

I have a cluster of 3 Ubuntu nodes running in VMs in the lab and want to take it now to production. Hetzner Online hetzner.de offers some good value dedicated servers, so I rented 3 machines, connected with a gigabit switch. My intention is to…
merlin
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Icinga2 dependecies of devices on HA

I would like to configure a Host-to-Host dependency on Icinga2, however, one of the Hosts has an HA configuration, so I need the to trigger it only when both HA devices are down. Suppose this scenario: Let's say I have all these devices on Icinga2.…
lithiium
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Can my redundant network setup be made more robust?

With my current design I have a DL380 Gen9 running ESXi. It has redundant NICs cabled to two different switches. Those switches in turn are both cabled to a third switch that allows my workstation to be connected. My testing so far has shown the…
Digital ink
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Loadbalancing and HA with SolrCloud?

I have a LAMP Application running with solr 3.x on one server for several years now. Now I am migrating due to heavy load to a setup with two dedicated machines where all services are loadbalanced via 2 keepalived HAProxy Servers. The only thing…
merlin
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